The gold finish probably was anodizing. Your choices are to polish it, paint it, or re-anodize it. re-anodizing it means pulling it and shipping it to a "plating" house that can accomodate something that big--not easy to find. Painting means special prep, primer, and paint--not cheap and not as long-lasting as anodizing. No real metallic golds, either.

Polish and living with whatever you have, just shinier, may be the only practical solution.